commanddemo.java

jBuilderX无线应用开发源代码

import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.*;

public class CommandDemo extends MIDlet implements CommandListener
{
	private Display display;

	private TextBox textBox;
	private List list;

	//定义程序中使用的命令
	private final static Command exit = new Command("Exit", Command.EXIT, 1);
	private final static Command back = new Command("Back", Command.BACK, 1);
	private final static Command ok = new Command("OK", Command.OK, 1);

	public CommandDemo(){
		//创建含有4个选项的List
		String[] options = {
            "Option A", 
            "Option B", 
            "Option C", 
            "Option D"
        };
        list = new List("Exclusive", Choice.EXCLUSIVE, options, null);
		//向List中添加2个命令
		list.addCommand(exit);
		list.addCommand(ok);
		//设置List的命令监听器
		list.setCommandListener(this);

		//创建TextBox，用于显示用户选择的信息
		textBox = new TextBox("Selected","",256,0);
		//向textBox中添加3个命令
		textBox.addCommand(exit);
		textBox.addCommand(back);
		textBox.addCommand(ok);
		//设置TextBox的命令监听器
		textBox.setCommandListener(this);

	}

	public void startApp(){
		//程序刚运行时，显示List屏幕
		display=Display.getDisplay(this);
		display.setCurrent(list);
	}

	public void pauseApp(){
	}

	public void destroyApp(boolean unconditional){
	}

	public void commandAction(Command c, Displayable d){
		//如果是exit命令，则退出程序
		if(c == exit){
			destroyApp(false);
			notifyDestroyed();
		}
		//如果是back命令，则把List屏幕设置为当前显示的界面
		else if(c == back){
			display.setCurrent(list);
		}
		//如果是ok命令，分2种情况处理
		else if(c == ok){
			//若该命令由List屏幕发出，则使用textBox屏幕显示用户在List中选择的选项
			if(d == list){
				String selected=list.getString(list.getSelectedIndex());
				textBox.setString(selected);
				display.setCurrent(textBox);
			}
			//若该命令由textBox屏幕发出，则使用textBox中的文本内容替换原来List选项元素的内容
			if(d == textBox){
				String modified = textBox.getString();
				list.set(list.getSelectedIndex(),modified,null);
				display.setCurrent(list);
			}
		}
	}
}